Formaldehyde-free durable press finishing agent

ABSTRACT

The present invention relates to a durable press finish composition, which contains a crosslinker for giving wrinkle-free performance to fabrics, a catalyst, and an additive allowing reductions in strength and whiteness of fabrics to be minimized. As the crosslinker, there is used glyoxal containing no formaldehyde. As the catalyst, there is used one selected from aluminum salt, magnesium salt, citric acid and a mixture thereof. As the additive, there is used sodium tetraborate, sodium peroxoborate, sodium chlorite, or sodium hydrogen sulfate.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a durable press finishing agentcontaining no formaldehyde harmful to the human body, and moreparticularly, to a durable press finish composition, which contains:glyoxal as a crosslinker; ethylene glycol or diethylene glycol as anagent for modifying the crosslinker; aluminum salt, magnesium salt orcitric acid as a catalyst for imparting wrinkle-free performance tofabrics; and sodium tetraborate, sodium peroxoborate, sodium chlorite orsodium hydrogen sulfate as an additive for preventing a reduction instrength of fabrics and for increasing the whiteness of fabrics.

2. Background of the Related Art

Durable press finishing, which is also called the wash and wearfinishing or the DP finishing, is conducted for the purpose ofartificially forming crosslinkages at a non-crystalline region ofcellulose forming cotton fabrics to increase the elastic limit of thecotton fabrics, thereby giving wrinkling-free performance and shapestability to the cotton fabrics.

A crosslinker which has been most frequently used till now in theindustrial durable press finishing of cotton fabrics isdimethyloldihydroxyethyl urea (DMDHDU) which forms ether-typecrosslinkages with the hydroxyl group of cellulose. However, thiscrosslinker generates formaldehyde harmful to the human body, and thus,is currently used in a limited manner. Currently, there are activelyprogressed studies on polycarboxylic acids, which form ester-typecrosslinkages with the hydroxyl group of cellulose and do not generateformaldehyde. Among them, butanetetracarboxylic acid where four adjacentcarbon molecules are attached to carboxylic acid is known as having themost excellent effect. However, this butanetetracarboxylic acid isdisadvantageous in that it can cause the eutrophication of lakes orrivers upon the durable press finishing of fabrics with it due to aphosphorus component of sodium hypophosphite known as the most excellentcatalyst. Furthermore, it can cause a change in color tone depending ona dye upon dying and also is highly expensive such that it cannot beused in industrial applications. Thus, there is an urgent need for acrosslinker, which does not generate formaldehyde harmful to the humanbody and allows the finishing costs of fabrics to be reduced.

Meanwhile, although glyoxal is used in the synthesis of DMDHEU, it mayalso give excellent wrinkle-free performance by itself. Moreover,glyoxal has various advantages as compared to other crosslinkers. First,it has low costs and thus allows the finishing costs of fabrics to bereduced. Also, it is supplied in a highly stable aqueous solution, andthus, considerably easily handled. In addition, it has little or nopoisonous character, and thus, can be used as a crosslinker having noharmful effect on the human body. However, when aluminum salt is used asa catalyst in durable press finishing using glyoxal as a crosslinker,fabrics can give excellent wrinkle-free performance but isdisadvantageous in that serious reductions in strength and whiteness offabrics can be caused.

SUMMARY OF THE INVENTION

Accordingly, has been made to solve the above-mentioned problemsoccurring in the prior art, and an object of the present invention is toprovide a durable press finish composition wherein glyoxal, which isinexpensive and substantially non-poisonous to the human body, is usedas a crosslinker, and a catalyst of a kind and amount, that are selectedsuch that the glyoxal can give fabrics wrinkle-free performance which isequal or superior to the prior crosslinkers, is used.

Another object of the present invention is to provide a durable pressfinish composition, which can minimize reductions in strength andwhiteness of fabrics.

To achieve the above objects, the present invention provides a durablepress finish composition, which comprises: a crosslinker for givingwrinkle-free performance to fabrics, which consists of glyoxal dissolvedin water at a concentration of 3-10% by weight; an agent for modifyingthe crosslinker, which is selected from ethylene glycol and diethyleneglycol and contained at a molar ratio of 1:1 relative to the glyoxal; acatalyst selected from aluminum sulfate and a mixture of magnesiumchloride and citric acid, the aluminum sulfate being contained at amolar ratio of 0.01-0.08 relative to the glyoxal, and the mixture ofmagnesium chloride and citric acid being contained at a molar ratio of0.1-0.6 relative to the glyoxal, the citric acid being contained at amolar ratio of 0.1-0.5 relative to the magnesium chloride; and anadditive selected from sodium tetraborate, sodium peroxoborate, sodiumchlorite and sodium hydrogen sulfate wherein the sodium tetraborate orsodium peroxoborate is contained at a weight ratio of 0.1-0.6% relativeto the composition, the sodium chlorite is contained at a weight ratioof 0.01-0.06% relative to the composition, and the sodium hydrogensulfate is contained at a weight ratio of 0.01-0.08% relative to thecomposition.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinafter, the present invention will be described in detail.

The present invention relates to a durable press finish composition,which contains: glyoxal as a crosslinker for imparting wrinkle-freeperformance to fabrics; ethylene glycol or diethylene glycol as an agentfor modifying the crosslinker; aluminum salt, magnesium salt or citricacid as a catalyst; and sodium tetraborate, sodium peroxoborate, sodiumchlorite or sodium hydrogen sulfate as an additive.

Formula 1 below shows the chelation of three compositions of glyoxalavailable as a 40% aqueous solution with a metal catalyst. ReactionScheme 1 below shows the reaction between cellulose, glyoxal andethylene glycol.

Formula 2 below shows the structure of ethylene glycol, which is used asan agent for modifying the crosslinker in the present invention.HOCH₂CH₂OH  [Formula 2]

Formula 3 below shows the structure of diethylene glycol, which is usedas an agent for modifying the crosslinker in the present invention.HOCH₂CH₂OCH₂CH₂OH  [Formula 3]

Formula 4 below shows the structure of aluminum sulfate, which is usedas a catalyst in the present invention. As the catalyst, there can beall hydrates where x is 14-18, and preferably 16.Al₂ (SO₄)₃.xH₂O wherein x=14 to 18.  [Formula 4]

Formula 5 below shows the structure of magnesium chloride, which is usedas a catalyst in the present invention.MgCl₂.6H₂O  [Formula 5]

Formula 6 below shows the structure of citric acid, which is used as acatalyst in the present invention.

Formula 7 below shows the structure of sodium tetraborate, which is usedas an additive in the present invention.Na₂B₄O₇  [Formula 7]

Formula 8 below shows the structure of sodium peroxoborate, which isused as an additive in the present invention.NaBO₃.4H₂O  [Formula 8]

Formula 9 below shows the structure of sodium chlorite, which is used asan additive in the present invention.NaClO₂  [Formula 9]

Formula 10 below shows the structure of sodium hydrogen sulfate, whichis used as an additive in the present invention.NaHSO₄  [Formula 10]

Formula 11 below shows the structure of sodium phosphate monobasic,which is used as a buffer in the present invention.NaH₂PO₄  [Formula 11]

In preparing the durable press finish composition according to thepresent invention, glyoxal of Formula 1 is dissolved in water at aweight ratio of 3-10%, to which one of ethylene glycol and diethyleneglycol represented by Formulas 2 and 3, respectively, is added at amolar ratio of 1:1 relative to the glyoxal. To this mixture, thecatalyst of Formula 4, 5 or 6 is added at a specified amount, and then,the additive of Formula 7, 8, 9 or 10 is added at a specified amount,thereby giving the durable press finish solution composition.

Fabrics are dipped in the prepared solution to sufficiently wet themwith the solution, and then, passed through padding rollers and theseprocedures are repeated one time. The fabrics wet with the solution arepre-dried on a tenter at 80-100° C., and then, thermally treated at atemperature of 130-180° C. to form crosslinkages between cellulosemolecules in a non-crystalline region of celluloses. The thermallytreated fabrics are sufficiently washed with water at 50° C., and then,dried on a tenter at a temperature of 80-100° C., thereby completing thedurable press finishing of the fabrics.

In the present invention, glyoxal as a crosslinker for impartingwrinkle-free performance to fabrics is preferably dissolved in water ata concentration of 3-10% by weight. If its concentration in water islower than 3% by weight, it cannot impart wrinkle-free performance tofabrics, and if its concentration in water is higher than 10% by weight,a reduction in strength of fabrics will be caused.

Meanwhile, ethylene glycol or diethylene glycol as an agent formodifying the crosslinker is preferably used at a molar ratio of 1:1relative to the glyoxal. In this case, ethylene glycol or diethyleneglycol causes a change in length and shape of the crosslinkage formedbetween fibers, and thus, has a positive effect on the wrinkle-freeperformance of fabrics.

Although all metal salt catalysts or organic acid catalysts serving asLewis acid in aqueous solution may be used as a catalyst in the presentinvention, it is preferable to use aluminum sulfate, magnesium chloride,citric acid or a mixture thereof. If aluminum sulfate is used at a molarratio higher than 0.08 relative to glyoxal as a crosslinker, it willcause a serious reduction in strength and whiteness of fabrics, and ifit is used at a molar ratio lower than 0.01 relative to glyoxal, itcannot give fabrics wrinkle-free performance. Also, the amount ofaluminum sulfate used will vary depending on the kind of fabrics used.Magnesium chloride, when used alone, cannot give fabrics wrinkle-freeperformance, but the use of a mixture of magnesium sulfate and citricacid can impart high-level wrinkle-free performance to fabrics. In thiscase, magnesium chloride is preferably used at a molar ratio of 0.1-0.6relative to glyoxal, and citric acid is used at a molar ratio of 0.1-0.5relative to magnesium chloride.

Furthermore, the additive used in the present invention acts to preventthe reduction of strength and whiteness of treated fabrics bycompetition with the catalyst in the reaction between cellulose and thecatalyst. In the case where aluminum sulfate or a mixture of magnesiumchloride and citric acid is used as a catalyst, the additive of Formula8 or the additive of Formula 9 in the present invention is preferablyused at a weight ratio of 0.1-0.6% relative to the solution composition.If the additive is used at the amount of less than 0.1% by weight, itcannot serve to prevent the reduction of strength and whiteness offabrics, and if it is used at the amount of more than 0.6, it willadversely affect the wrinkle-free performance of fabrics. In the casewhere aluminum sulfate or a mixture of magnesium sulfate and citric acidis used as a catalyst, the additive of Formula 10 is preferably used atthe amount of 0.01-0.08% by weight relative to the solution composition.In order to give optimal wrinkle-free performance to fabrics whilepreventing the strength and whiteness of fabrics from being reduced, itis preferable to use a very small amount of sodium phosphate monobasic,a buffer of Formula 12.

As described above, the present invention provides the durable pressfinish composition wherein glyoxal, which contains no poisonousformaldehyde, has low costs and can give fabrics excellent wrinkle-freeperformance, is used as a crosslinker, and at the same time, thecatalyst and additive of suitably selected kinds and amounts, that areselected such that the crosslinker can give optimal wrinkle-freeperformance to fabrics, are used.

The present invention will hereinafter be described in further detail byexamples and comparative examples. It should however be borne in mindthat the present invention is not limited to or by the examples.

EXAMPLE 1

Gloxal as a crosslinker was dissolved in water at a concentration of 5%by weight, to which aluminum sulfate as a catalyst was added at a molarratio of 0.04 relative to the glyoxal, thereby producing the finishingsolution 1. To the finishing solution 1, each of ethylene glycol anddiethylene glycol was added at a molar ratio of 1:1 relative to theglyoxal, thereby producing the finishing solutions 2 and 3,respectively. Then, 100% cotton fabrics are finished with each of thefinishing solutions 1, 2 and 3 by a pad-dry-cure method. In this case,the pad was carried out in a 2dip-2nip manner such that a wet pick-up isset at about 95%. The dry is carried out at 85° C. for 3 minutes and thecure at 150° C. for 3 minutes.

The fabrics which had been finished under the above conditions weremeasured for their wrinkle recovery angle according to AATCC Test Method66-1998. Also, their tensile strength was measured according to ASTM D1682-64 and their whiteness index was measured by X-Ritespectrophotometer according to ASTM E 313. The amount of freeformaldehyde from the finished fabrics was measured according to JIS L1041 A.A METHOD B. The results showed that the wrinkle recovery angle ofthe finished fabrics was superior to that of fabrics finished with theprior durable press finishes, and their tensile strength and whitenessindex were similar to those of the fabrics finished with the priordurable press finishes. However, there was no detection of formaldehydefrom the finished fabrics.

EXAMPLE 2

The additive of Formula 10 was added to the finishing solution 2produced in Example 1, at a molar ratio of 0.25-1.5 relative to aluminumsulfate as a catalyst, thereby producing a finishing solution. 100%cotton fabrics were finished with this finishing solution and measuredfor their physical properties in the same manner as in Example 1. Theresults showed that the wrinkle recovery angle of the finished fabricswas gradually reduced with an increase in concentration of the additive,but higher than that of fabrics finished with the prior durable pressfinishes. Also, it could be found that their tensile strength andwhiteness index were gradually increased with an increase inconcentration of the additive. Thus, it could be found that all thephysical properties of the fabrics finished with this finishing solutionwere equal or superior to fabrics finished with the prior durable pressfinishes. As in Example 1, there was no detection of formaldehyde in thefabrics finished with the solution of Example 2.

EXAMPLE 3

Glyoxal as a crosslinker was dissolved in water at a concentration of5%, to which a mixture of magnesium chloride and citric acid as acatalyst was then added, thereby producing a finishing solution. 100%cotton fabrics were finished with this finishing solution in the samemanner as in Example 2. In this case, the molar ratio of magnesiumchloride to glyoxal was 0.2, and the molar ratio of citric acid tomagnesium chloride varied in the range of 0.1-0.5.

The finished cotton fabrics were measured for their physical propertiesin the same manner as in Example 1. The results showed that the wrinklerecovery angle of the fabrics finished with the solution of Example 3was superior to fabrics finished with the prior durable press finishes.But their tensile strength and whiteness index were somewhat reduced,and there was no detection of formaldehyde in the fabrics finished withthe solution of Example 3.

EXAMPLE 4

To the finishing solution of Example 3 where the molar ratio of citricacid to magnesium chloride was set at 0.2, each of additives of Formulas7 and 8 was added at amounts varying in the range of 0.1-0.6% by weightrelative to the weight of the finishing solution, thereby producing afinishing solution. 100% cotton fabrics were finished with thisfinishing solution, and measured for their physical properties. Theresults showed that their wrinkle recovery angle was somewhat lower thanthat of Example 3, but higher than that of fabrics finished with theprior durable press finishes. Also, their tensile strength and whitenessindex were equal to those of fabrics finished with the prior durablepress finishes. Furthermore, there was no detection of formaldehyde inthe fabrics finished with the solution of Example 3.

EXAMPLE 5

Glyoxal as a catalyst was dissolved in water at a concentration of 5%,to which aluminum sulfate as a catalyst was added at a molar ratio of0.04 relative to the glyoxal. To this solution, each of additives ofFormulas 7 and 8 was added at amounts varying in the range of 0.1-0.6%by weight relative to the weight of the solution, thereby producing afinishing solution. 100% cotton fabrics were finished with the finishingsolution and measured for their physical properties in the same manneras in Example 1. The results showed that the wrinkle recovery angle ofthe finished fabrics was slightly reduced with an increase inconcentration of the additives, but higher than that of fabrics finishedwith the prior durable press finishes. As in Example 1, there was nodetection of formaldehyde in the fabrics finished with the solution ofExample 5.

EXAMPLE 6

Glyoxal as a crosslinker was dissolved in water at the concentration of5%, to which each of a mixture of magnesium chloride and citric acid,and aluminum sulfate, as a catalyst, was added. To this solution, sodiumchlorite of Formula 9 as an additive was added at amounts varying in therange of 0.01-0.06% by weight relative to the weight of the solution,thereby producing finishing solutions. 100% cotton fabrics were finishedwith each finishing solution in the same manner as in Example 1. Also, abuffer of Formula 11 was added to the respective finishing solutions ata small amount. 100% cotton fabrics were finished with the finishingsolutions containing the buffer in the same manner, and compared to thefabrics finished with the finishing solution containing no buffer. Thefabrics finished with such finishing solutions were measured for theirphysical properties in the same manner as in Example 1. The resultsshowed that all the physical properties (particularly, whiteness index)of the fabrics finished with the solutions of Example 5 were superior tofabrics finished with the prior durable press finishes. Also, there wasno detection of formaldehyde in the fabrics finished with the solutionsof Example 5.

As described above, the present invention provides the durable pressfinish composition wherein glyoxal, which contains no formaldehydeharmful to the human body, has low costs and can give excellentwrinkle-free performance to fabrics, is used as a crosslinker, and thecatalyst and additive of kinds and amounts suitable to give optimalwrinkle-free performance to fabrics are used. Thus, according to thedurable press finish composition of the present invention, seriousreductions in strength and whiteness of fabrics, which are problemsoccurring in the prior durable press finishes, can be prevented. Inaddition, the inventive durable press finish composition can givefabrics wrinkle-free performance that is equal or superior to the priorcrosslinkers.

While the present invention has been described with reference to theparticular illustrative embodiments, it is not to be restricted by theembodiments but only by the appended claims. It is to be appreciatedthat those skilled in the art can change or modify the embodimentswithout departing from the scope and spirit of the present invention.

1. A durable press finish composition, which comprises: a crosslinkerfor giving fabrics wrinkle-free performance, which consists of glyoxaldissolved in water at a concentration of 3-10% by weight; an agent formodifying the crosslinker, which is selected from ethylene glycol anddiethylene glycol and contained at a molar ratio of 1:1 relative to theglyoxal; a catalyst selected from aluminum sulfate and a mixture ofmagnesium chloride and citric acid, the aluminum sulfate being containedat a molar ratio of 0.01-0.08 relative to the glyoxal, and the mixtureof magnesium chloride and citric acid being contained at a molar ratioof 0.1-0.6 relative to the glyoxal, the citric acid being contained at amolar ratio of 0.1-0.5 relative to the magnesium chloride; and anadditive selected from sodium tetraborate, sodium peroxoborate, sodiumchlorite and sodium hydrogen sulfate wherein the sodium tetraborate orsodium peroxoborate is contained at a weight ratio of 0.1-0.6% relativeto the composition, the sodium chlorite is contained at a weight ratioof 0.01-0.06% relative to the composition, and the sodium hydrogensulfate is contained at a weight ratio of 0.01-0.08% relative to thecomposition.